Compensation of the influence of the pressure of the working medium in sealing joints with thin-walled elements

Abstract

One of the ways to improve sealing joints, particularly valves operating at high pressures, temperatures, various aggressiveness and in conditions of operational changes (for example, pressure pulsation) of the working environment, can be to partially or completely unload (counterbalance) them. The unloading of the sealing joint is usually understood as the compensation of the influence of the pressure of the working medium on the valve gate elements in order to ensure a constant sealing pressure in the sealing joint. The unloading of the sealing joint is achieved due to a certain design of the valve gate, which is influenced upon by the pressure of the sealed medium, as a result of which the effect of self-sealing of the joint can be achieved (with partial unloading). Beyond that, using metal elements as a spool and seat guide in the valve gate allows us to achieve certain advantages and get rid of the disadvantages inherent in joints with polymer seals. At the same time, using a seat guide with reduced rigidity (a thin-walled shell) as a seal makes it possible to reduce the sealing force, mass-dimensional parameters, to provide the constancy of the sealing force around the seal perimeter (to avoid the problem of choosing the deflection of the seat guide shape). The proposed diagram of the unloaded valve differs from the existing ones primarily by the absence of a rigid connection between the stem and the spool of the valve. This will allow minimizing the transfer of the influence of the working medium pressure from the stem to the valve spool, which in turn will make the seat guide even more thin-walled. Among other things, a decrease in the reduced stiffness of the seat guide also makes it possible to reduce the sealing load in the contact zone of the spool and seat guide, but these issues are beyond the scope of this article and have not been considered.